Automatic transmissions generally include at least one planetary gear set and a plurality of shift elements. The shift elements selectively engage components of the planetary gear sets in order to hinder or prevent rotation of the components. Selective actuation of the shift elements adjusts the gear ratio of the automatic transmission and shifts the automatic transmission between its various gears.
Certain automatic transmissions include dog clutch shifting elements. During various gear shifts, the dog clutch is engaged or closed. Engaging the dog poses certain challenges. For example, the dog clutch is generally synchronized prior to engaging the dog clutch. When the dog clutch is synchronized, components of the dog clutch rotate at a common speed and may engage each other more easily. Conversely, such components may grind against each other and be damaged if the dog clutch is engaged while the dog clutch is not synchronized. However, synchronizing the dog clutch can be difficult and/or time consuming. For example, a separate synchronizing mechanism can consume valuable space within a transmission and add to an overall cost of the automatic transmission.
Certain conditions can also hinder or prevent actuation of the dog clutch. For example, even when the dog clutch is synchronized, teeth of the dog clutch can butt against one another and hinder or prevent engagement of the dog clutch. As another example, the teeth of the dog clutch can stick and hinder or prevent actuation of the dog clutch even when the dog clutch is synchronized.
Accordingly, a method for synchronizing a dog clutch of an automatic transmission would be useful. In particular, a method for synchronizing a dog clutch of an automatic transmission that also includes steps for ameliorating tooth butting and/or spline locking of the dog clutch would be useful.